Matplotlib doesn't show the figure window from within a virtualenv. I've tried many combinations (e.g. intalling using pip, using easy_install, compiling from source, using --system-site-packages, different versions, etc.) with no luck. The test that makes me think is a virtualenv issue is that if I try to use my working system-wide matplotlib from virtualenv, I don't see a figure. In other words, if I run this:

[~]$ python plotTest.py

it works ok (shows the figure). Then, if I create a virtualenv with--system-site-packages and run the same script, it doesn't work. That is:

[~]$ virtualenv --system-site-packages vEnv[~]$ source vEnv/bin/activate(vEnv)[~]$ python plotTest.py

fails (it hangs and doesn't even return). I need to kill the process.
Btw, theplotTest.py if the following:

import matplotlibimport matplotlib.pyplot as pltprint "Backend: ", matplotlib.rcParams['backend']plt.plot([1,2,1])plt.show()

FWIW, in both cases I do see the line printingMacOSX as the backend.